Firefighters in California increased their containment of a large wildfire in mountains north of Los Angeles on Monday after a weekend of wind-driven growth.

The Post Fire was 8% surrounded after scorching nearly 23 square miles (60 square kilometres) and forcing the evacuation of at least 1,200 campers, off-roaders and hikers from the Hungry Valley recreation area on Saturday.

“That 8% is good because it means we are increasing and bolstering our containment lines,” said Kenichi Haskett, a Los Angeles County Fire Department section chief.

Firefighters hoped to hold the fire at its current size, but further growth was possible, Mr Haskett said.

A firefighter sprays water on a burning outbuilding as the Point Fire spreads in Healdsburg, California
A firefighter sprays water on a burning outbuilding as the Point Fire spreads in Healdsburg, California (Noah Berger/AP)

The fire broke out as weather turned hot and windy in a region where grasses spawned by a rainy winter have long since dried out and easily burn.

The massive columns of smoke that marked the fire’s initial rampage were gone by Monday morning. But Sunday’s smoke drifted some 225 miles (360km) north-west across the Mojave Desert. Nevada air quality officials issued an alert advising children, older adults and people with respiratory and heart disease to stay indoors.

In Northern California, a wildfire sparked on Sunday prompted evacuation orders and warnings for a sparsely populated area near Lake Sonoma. It was 20% surrounded on Monday after charring nearly two square miles about 80 miles (130km) north of San Francisco, and destroyed at least one structure.

Ben Nicholls, division chief of the Cal Fire district in area covering the fire, said on Monday morning that fire activity subsided overnight.

“Forecasted winds are supposed to be less than we experienced yesterday, which should allow the resources assigned for this operational period to build and strengthen the control lines that were put in place yesterday,” Mr Nicholls said.

The Southern California fire erupted on Saturday afternoon in Gorman, about 60 miles (100km) north-west of Los Angeles. Two structures burned within the evacuated recreation area.

Officials also warned residents of Castaic, home to about 19,000 people, that they should prepare to leave if the fire pushed farther south.

“If you’re in a warning area, be prepared with a ‘go bag,’ with overnight clothes and your cellphone, your medicines, your glasses. Have your car fuelled up,” said Mr Haskett. “Be ready to evacuate.”

About 75 miles (120km) to the east, the nearly two-square-mile (Five square kilometres) Hesperia Fire was 30% contained after no overnight growth. The fire erupted on Saturday and forced road closures and evacuation warnings in San Bernardino County.